Indicator for telephone switching apparatus.



H. W. DUNBAR. INDICATOR FOR TELEPHONE SWITGHING APPARATUS.

APPLICATION FILED A2118. 1910.

1,012,066. y Patented 11901111911.

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I/l//nessesf v jf/gj by @QT UNITED STATES PATENT OFFICE.

HOWARD W. DNBAR, OF NEWARK, NEW JERSEY, ASSIGNOR T WESTERN ELECTRIC COMPANY, 0F NEW YORK, 1\T. Y., A CORPORATION OF ILLINOIS,

INDICATOR FOR TELEPHONE SWITCHING APPARATUS.

Specification of Letters Patent.

rammed Dec. 19, 1911.

Applica-tion 'tiled April 8, 1910. Serial No. 554,158.

To all whom it may concer/n.:

Be it known that l, Hownnn 1V. DUNBAR, citizen of the United States, residing at Newark, in the count-y of Essex and State of New Jersey, have invented a certain new and useful Improvement in Indicators for Telephone Switchingr Apparatus, of which the following is a full, clear, concise, and exact description.

My invention relates to telephone switchinal appliances of the type having` a pair of s\\'itcliactuating keys and more particularly to switchingl appliances having self-retract ing' keys which require additional indicating devices. and its object is to provide a mechanical indicatinfi' device for use with a telephone switching` appliance having a pair of self-retracting keys which will give the operator a visual indication of the key last ac* tuated, which shall be of few parts, cheap to man ufacture, readily applied to the frame et' the appliance, and when so applied shall occupy little space thereon.

In accordance with this invention, a visual mechanical indicator is arranged to` be associated with or applied to a telephone switchimg` appliance embracing a pair of switch-actuating keys, and comprises a target slidable in a channel in the top of the frame between said keys, the target being' arranged to be moved by either of said keys to assume alternative positions of display to ,indicate which key of the pair was last actuated. A. very compact and easily-assembled structure of this sort is secured by providing :1n-actuating lever pivoted upon a horizontal axis below the table. or frame, the upper end of said lever engaging the target, and suitable connections between the lever and keys being,l provided.` `'The lever is preferably pivoted in a bracket which may oe readily mounted upon the side of the vertical leg' of the frame which supports the switch "Wings i The 2 ccompanying drawings illustrate the invention applied to a telephone switchingappliance having a pair of rocking levers, wherein- Figure 1 is a side elevation part-lv in section; Eig. 2 is a plan; Fig. 3 is a fragmew tary sectional elevation .on line 3-3 of Fig. 2; Fig. Li is a sectional view on line 4 4 of Fig. l and Eig. 5 indicates a series of perspective views of the lever and its supporting bracket, as well as the slidable indicating' plate and its mounting.

The 'key shown comprises two U-shaped metallic units 1, 2. each bridged at the base by metallic members 3, 4, upon each of which is mounted in suitable insulating mountings 5, G, a set of switch springs 7, 8. Each of said units 1, 2 is clenched 'fi atrough shaped metallic bridge 9 faced with an 'insulating strip 10. Each set of switch springs 7, S has a. normal resting contact 11, 12 and an alternate Contact 13, 14. The middlel switch springs 15, 16 of the respective sets 7, 8 projects above the outer two and the spring 15 is adapted to be deflected by an insulated roller 17 `carried by'a rocking lever 18 pivoted between-the arms of the bridging member 9, while the middle spring' 16 of the set of switch springs 8 is adapted to be defiected by a. similar roller 19 c rried by a rocking lever 20, 'similarly pivoted between the arms of the bridging member 9. Each of these middle springs is adapted to return the corresponding rocking lever to its normal intermediate position upon the release of the operating pressure. Riding in a channel 21 in the insulating face plate 10 is an indicator 22 somewhat less in length than the channel, and of less thickness than the depthof said channel. Bridging this channel and secured by screws 23, 24 to the )1 85 face plate 10 is an esenteh'eon plate 25 hav-i ing two openings 2G, 2T servingi as windows and before either of which the indicator 22 is adapted to show in one of its alternate p0- sitions. A transparent protecting shield 28 lies between the said escutcheon plaie andthe indicator. In the center of the indicate?.w 22 is an opening or slot adapted to acco `nnodate a ting-er 2t) of an angle piece 3() frictionally pivoted by the spring washer 81 and screw 32 to a right angled extension 33 of a bracket 34 secured by screws 35, 36 to the inner side of the unit 1. This angle piece 30 has an arm 40 adapted when the indicator is exposed at the window adjacent the right hand lever to be engaged, upon the actuation of lever 20, by the lug 38 carried upon its cam port-ion 39 to rotate said angle piece, whereupon iis finger 29 shifts the indicator 22 to the Window 26 adjacent the left hand lever 18. Similarly a lug 37 of said angle piece 30 is adapted after the indica-tor has` been so moved and is' exposed before Window 26 adjacent lever 18, as shown in Fig. 8, to be engaged by a lever L.t1 frictionally pivoted to the cam portion 42 of lever 18, whereupon the linger 29 shifts the indicator back again to its former position before the Window 27 adjatent lever 20. It

will thus be evident that upon the actuation of either set of switch springs '7 or 8 bv its corresponding lever shoivsat the Window adjacent the opposite lever and by having' this target a contrastive color, for instance White, since the face plate shown is black, the operator Will be enabled to determine at a. glance which of the tivo levers she had last actuated if it becomes necessary that she operate the same one again.

Having thus described my invention, I claim y l. In combination with a. telephone switching appliance having a pair of switchactuating keys, a supporting frame, indicating mechanism comprising a target slidable in a channel in said frame and capable of being displayed in alternative positions, a lever engaging said target, and connections between said lever and keys whereby the actuating movement ot the keys is transmitted to said target to cause it to assume one of its alternative positions to indicate the key last actuated.

2. n combination .with a telephone switching applianpe having a pair ot sivitclractuis 01- 2o, the target 2a ating keys, a supporting frame, indicating mechanism mounted upon said frame comprising a target capable of assuming alternative display positions, a lever mounted upon said frame to rotate about a. horizontal axis and adapted to displace said target, and connections between said lever and keys whereby the actuating movement of the keys is transmitted to said target.

3. In a key structure,the combination with a mount-ing frame, sets of switch springs mounted thereon, a pair of rocking levers for actuating said springs, an insulated face plate for said frame having a channel located between said keys, an escutcheon plate covering said channel and having a pair of Windows, an indicating plate slidable in said channel and adapted to be .displayed at either ot' said Windows, an angle piece pivoted to said :trame to rotate about a horizontal axis and having a finger extending through openings in said frame and insulating face plate and engaging a slot in said indicating plate, and connections between said lever and keys whereby the indicator remains displayed at the Window adjacent the key opposite that last actuated.

In Witness whereof, I lhereunto Subscribe elmy name this (ith day of April A.. D.. 191.0.

HOWARD W. DUNBAR. Witnesses El. MoINTosH, h/.miean WAsHnURNeJn- 

